text: The chemical structure of compounds play an important role in binding to their target. The most important and necessary chemical group for the binding and activity of these compounds is the β-lactone (beta-lactone) ring which is the central pharmacophore. The β-lactone moiety is shown in red in the structures in the table below.
  Researches have shown that cleavage of the β-lactone ring results in loss of inhibitory activity of the inhibitors, which makes the β-lactone structure a crucial part in biological activity.
  The lactone ring structure binds irreversibly to the active site of the lipase and forms covalent bond, which leads to inhibition.
  Drugs of this class include:
  * Lipstatin, the first known lipase inhibitor, comes from a natural source. It has a β-propiolactone ring, which has a 2,3-trans-disubstituted linear alkyl chains located at the α- (C6) and β-site (C13) of the compound. It contains N-formyl-L-leucine amino acid connected to the β-alkyl chain via ester-bond. The structure of Lipstatin is shown in the table below.
  * Orlistat is a semi-synthetic compound, which has a similar structure to lipstatin. They differ only in the saturation of the β-alkyl chain, where orlistat is saturated while lipstatin has two double bonds in the side chain. The structure of orlistat is shown in the table from the last section.